This invention relates to franking systems in which franking machines are utilised to frank postal items with a value of postage charge and in which funding of the franking machines with credit for use in franking is effected remotely.
Franking machines for franking postal items and which are operated on a prepayment system are provided with a credit register which stores a value of credit for which payment has been made to a postal authority and which remains available for use in franking of mail items. Initially, upon payment to the postal authority a value is entered into the credit register corresponding to the payment. As items are franked with postage charges, the value in the credit register is decremented by the postage charges and hence represents the value remaining available for franking of postal items. When the value in the credit register has reduced to a predetermined value, which may be zero or a higher value, the accounting and control circuits of the franking meter prevent further franking operations until the user of the franking machine has purchased further credit from the postal authority and a corresponding credit value has been added into the credit register. For reasons of security, the user of the machine is not permitted to have access to the interior of the franking meter or to any of the accounting circuits of the meter. Accordingly the addition of credit to the credit register is not permitted to be effected by the user of the machine. In known franking machines, the franking meter is a portable module and when additional credit is to be entered in the meter the module is taken to the postal authority for resetting of the credit register. When the meter is returned to the postal authority for resetting the credit register, the postal authority is enabled to effect an auditing operation in which the contents of other registers such as a tote register which records the total value of franking issued by the meter and an item counter which records the number of items franked by the meter are read. The auditing operation enables the postal authority to check usage of the machine as recorded by the various registers to ensure that the data in the registers is in agreement with usage of the machine since the preceding auditing.
The need to take the meter to a postal authority centre is inconvenient and time consuming to users of franking machines. The machine is not operable while the meter is removed for resetting and hence users need to anticipate their need for credit in order to prevent interruption to franking of mail items. In addition, the postal authority has to provide a resetting service at a large number of locations, for example at every main post office, in order to provide adequate accessibility of the service to customers.
In order to overcome the inconvenience of removing the meter and taking it to a postal authority resetting centre remote resetting systems have been proposed and are used. In one system an electronic storage module is utilised to carry data between a postal authority resetting centre and franking machines at users locations. The module has credit data entered into and stored in it by the postal authority and after receipt thereof by the customer, the module is connected to the meter to enable the meter to read the credit data. The meter enters audit data into the module and upon return of the module to the postal authority, the postal authority reads the audit data and is enabled to carry out auditing of the usage of the meter. Thus the meter does not need to be removed from the franking machine for resetting and resetting is effected at the user's location. All data for the resetting of credit and auditing is carried by the module which is of sufficiently small size to sent as a mail item. In order to provide security for the data transported in the module, the module also carries a code in the form of a pseudo-random number which is compared with a corresponding pseudo-random number stored in the franking meter and in the postal authority resetting computer. The code in the module is compared with that in the meter or computer and, if there is a match, the data in the module is accepted as valid. The code is changed after each resetting transaction to prevent fraudulent resetting of the meter.
In another system resetting of the credit registers has been effected remotely by use of the telephone network for transmission of data. Communication between the franking meter and the telephone network has required the intervention of the user and in order to provide security and ensure resetting of the credit register with an authorised value of credit the user has been required to enter a code on the keypad of the telephone and to receive a code by voice transmission which then has to be entered by the user on the keyboard of the meter. The entry of a string of digits, which of necessity is meaningless to the user, is likely to lead to incorrect entry of the code and can necessitate repeated attempts to reset the meter.